Radio shielded ignition



Aug. 26, 1941. M. F. PETERS EI'AL' ammo sammmn mnnron Filed oi. 2. 1959 M51. V/LLE F. PE TEES HAPPY STONE Patented Aug. 26, 1941 Melville F.

Stone, Bound Brook, N. ,L, assignors Peters, Beltsville, Md., and R. Harry Metal Hose 00., a corporation of New Jersey Application October 2, 1939, Serial No. 297,616

11 Claims. (01. 123- 148) This invention relates to a simple and economical means for preventing radio waves liable to interfere with radio transmission, from emanating from an ignition system for an internal combustion engine,

Such interference is most likely to take place in vehiclespropelled by internal combustion engines, such as automobiles, aeroplanes, etc., which also carry radio receivers, because of the necessarily close proximity of the radio and i nition apparatus. According to the present invention, especially in connection with automobiles, it is proposed 8 with one terminal of the storage battery 9,

the other terminal of the storage battery beingv connected with the ground at I0.

From a point on the generator side of the filter in the connection between the generator andthe filter, namely at H, the ignition circuit extends through conductor l2, switch 13 for opening and closing the ignition circuit, the usual spark coil I4, well known distributor I6 having the required contacts and connections from which .extend wires l1 to the several spark plugs l8 mounted I on the engine cylinders I9, there being such numto confine the disturbing variations of current in the ignition'system to a certain portion of the system by means of a current filter, the portion having the disturbing currents being radio shielded, the apparatus being so arranged that the filtering arrangements'are reduced to a minimum andalso the ektent of theradio shielded apparatus is reduced, whereby economy of labor and materials and efficiency of the shielding of the ignition system is attained.

The main object of the invention is therefore to produce an efficient andeconomically constructed radio shielded ignition system of. thecharacter as indicated.

A further object of the invention is to reduce the filtering apparatus required in a radio shielded ignition system .of the character as indicated N Other and ancillary objects of the invention will appear hereinafter.

In the accompanying drawing which illustrates the invention-- Fig. 1 is a-diagrammatic view showing a radio shielded ignition system embodying the invention; and v Fig. -2 is a diagrammatic view showing'a modifled arrangement of a radio shielded ignition system embodying the invention. v

Referring to the drawing, and first to Fig. 1,

system suitable for use on an automobile but which, of course, may be used in any other application to which it may be suited. The 'apparatus comprises the usual electric generator I driven from the engine of an automobile, one

terminal of the generator being grounded at 2.

From the other, terminal of the generator connection is made through the conductor 3 withone terminal of a filter comprising the inductween the ends of the coil 4 and the metal casing 6 which is grounded at 1. The other terminal there is therein shown a radio-shielded ignition ber of,cylinde rs as is desired as is well understood, the timer and spark plugs and the connections beingarranged in a well-known manner to provide the sparks desired at. the spark plugs to cause suitable operation of the engine.

It willbe observed that there is a circuit from the ground at-2 through the generator I, the electric filter and the storage battery 9 to the ground at Ill-through which the generator will charge the battery when the voltage of the former predominates, revers'e-flow of the current, that is from the battery through the generator, being prevented by a well-known cut-out switch which is usually mounted upon the generator structure. At such times, however, as the voltage of the battery predominates, the battery will supply the ignition current to the spark plugs, the spark plug current being supplied by the generator when its voltage predominates over that of the battery. This is well-known and requires no further description.

The distributor is also .customarily mounted adjacent the generator and the generator, cutout switch, distributor and associated parts areenclosed in a metal casing 20 acting as a radio shield, such casing being grounded at 2. The wires l emerging from the casing 20 are enclosed in a metal radio shielding conduit 2| jointed to the casing 20, such conduit 2| having branch conduits 22, one for each'spark plug, surrounding the spark plug conductors from the conduit 2| to the spark plug, and also that I portion of the spark plug which extends'outside 7 tance coil 4, and the'condensers 5 connected be:

"of the engine block [9,, the metal conduits 22 being in contact with and therefore grounded upon the engine block 19. The spark coil H is enclosed by a metal radio shielding casing 23' grounded at 24, and the casing 23 is connected with the casing 20 .by a metal'radio shielding ,conduit 25 through" which pass theconductors extending between the said'casings. Also extendv of the inductionjcoil isrconnected by a conductor from he 58 th radio. h fl 7 conductor l5 and a suitable and casing'6 of the current filter is a metal radio shielding conduit 26 through which the con-' ductor 3 between the filter and the generator passes. Also from the conduit 25 radio shieldin metal conduits 21 and 28 extend to the radio shielding metal casing 29 which encloses the switch l3, the conduits 21 and 28 shielding the conductors l2 and 30 leading to and from the switch.

It will now be seen that all of the conductors and apparatus on the' generator side of the filter are radio-shielded and that disturbing variations of current are prevented from passing to the battery side of the filter \by means of the filtering operation so that no radio shielding ofthe conductorsor apparatus on the battery side of the filter is necessary.

It will further be observed that connections from the spark plugs to the battery and front the generator to the battery are made through acommon filter, so that an economy is effected from what would be the case if the spark plugs circuits not passing to the battery side 0! the filter.

With the arrangement of Fig. 2, the opening of the ignition switch 45 merely operates to open the connection of the battery with the spark plugs and will therefore operate to stop the ignition only when the ignition current is being supplied by the battery. This is the condition when the engine is idling" and the generator is running at such low speed that the battery voltage predominates. The cut-out switch will then be open and upon opening the switch 45 the spark plugs will be deprived 01 were connected with the battery through one filter and another filter were employed for connecting the generator with the battery.

Referring now to Fig. 2, the apparatus therein shown is similar to the apparatus of Fig. 1 exsiderable economy.

In the apparatus of Fig, 2, the generator 3| with the cut-out switch (not shown), the distributor 32 and appurtenant apparatus are enclosed in the radio shielding metal casing 33 grounded at 34. The wires 35 from the distributor-to the various spark plugs 38 mounted'in the cylinder blocks 3'! are radio shielded'by being enclosed in a radio-shielding conduit 38 from which extend the radio shielding conduits 39 to the spark plugs. One terminal of the generator 3| is connected with the casing 33 and thence to ground at 34 while the other terminal is connected by conductor 40 with one terminal of a filter comprising the inductance coil 4| connected at its ends by the condensers 42 with the metal radio shielding casing 43 which is grounded at 44. Theother terminal of the filter is connected through the ignition controlling switch 45 with one terminal of the storage battery 46, the other terminal of the battery being connected with ground at 41. From point 48 on the conductor 40, between the generator and the filter, an ignition circuit extends through the conductor 49, a usual spark coil 50, the conductor 5|,the distributor 32 and the conductors 35 to the various spark plugs .36 of the engine.

The spark coil 50 is enclosed and radio shielded by a metal casing 52 which is grounded at 53. From the casing 52 a radio shielding conduit 54 extendsto the casing 33 and from the conduit 54 a radio shielding conduit 55 extends to the casing 43. It thus be seen that all the wires and apparatus on the generator side of the filter are enclosed by radio shielding, while the apparatus and connections on the battery side of the filter require no shielding, the disturbing variations in the generator and ignition all current. In order, therefore, to stop the engine with the apparatus of Fig. 2, the engine ii first slowed down so that the cut-out switch open: and then the switch 45 is opened.

While the invention has been illustrated in what are considered its best applications, it may have other embodiments without departing tron: its spirit and is not, therefore, limited to the structures shown in the drawing.

What we claim is:

1. In an ignition system for an internal combustion engine, the combination with an electru generator, of a battery, an electric filter, conducting means connecting one terminal of salt generator with said filter, conducting means connecting said filter with one terminal of said battery, conducting means connecting the other terminal of said battery with the other terminal 01 said generator, one or more spark plugs, conducting means connecting said one or more spark plugs to a point on the said conducting mean:

between said generator and filter, radio shielding means for the electrical apparatus on tl'li generator side of said filter and a switch for cutting off the ignition current.

2. In an ignition system for an internal combustion engine, the combination with an electru generator, of a battery, an electric filter, conducting means connecting one terminal of said generator with said filter, conducting means connecting said filter with, one terminal of said battery, conducting means connecting the other terminal of said battery with the other terminal 01 said generator, one or more spark plugs, conducting means connecting said one or more spark plugs to a point on the said conducting means between said generator and filter, radio shielding :means tor the electrical apparatus on the gentery, conducting means connecting the other terminal of said battery with the other terminal 01 said generator, one or more spark plugs, conducting means connecting said one or more spark plugs to a point on the said conducting mean: between said generator and filter, radio shielding means for the electrical apparatus on the generator side or said filter and a switch for cutting ofi the ignition current, said switch being in series with a spark plug between the spark plug and said point on the connection between the filter and generator.

4. In an ignition system for an internal combustion engine, the combination with an electric plugs to a point on the said conducting means between said generator and filter, radio shielding means for the electrical apparatus on the generator side of said filter and a switch for cutting ofi the-ignition current, said switch being on the battery side of said filter. 5. In an ignition system for an internal combustion engine, the combination with a circuit including a generator, a current filter, a battery and an ignition circuit including one or more spark plugsand a spark coil, the ignition circuit being connected with the first mentioned circuit on the generator side of'said filter and means for I radio shielding the apparatus on the generator side of said filter.

6. In an ignition system for an internal combustion engine, the combination with a circuit bustion engine, the combination with an electric circuit including a generator and a battery, of an ignition circuit including one or'more spark plugs, and a spark coil, the generator and said ignition circuit having a common connection with said battery, 9. current filter in said comincluding a generator, a current filter, a battery and an ignition circuit including one or more spark plugs, a switch controlling the ignition and a spark coil, the ignition'circuit being connected with the first mentioned'circuit on the generator side of said filter and means for radio shielding the apparatus on the generator side of said filter.

" '7. In an ignition system for an internal combustion engine, the combination with a circuit including a generator, 9. current filter, a battery and a switch connected between the filter and battery for controlling the ignition current, and an ignition circuit including one or. more spark plugs and a spark coil, the ignition circuit being connected with the first mentioned circuit on the generator side of said filter and means for radio shielding the apparatus on the generator side of said filter.

8. In an ignition system for an internal common connection, a switch controlling the ignition and means for radio shielding the apparatus on the generator side of said filter.

9. In an ignition system for an internal com.-

bustion engine, the combination with an"electric circuit including a generator and a battery, of an ignition circuit including one or more spark plugs, a spark coil and a switch controlling the ignition, the generator and ignition circuit having a common connection with said battery, a current filter in said common connection and means for radio shielding the apparatus on the generator side of the filter.

10. In an ignition system for an internal combustion engine, the combination with an electric circuit including a generator and a battery, of an ignition circuit including one or more spark plugs and a spark coil, the generator and said ignition circuit having a common 'connectionwith said battery, a current filter in said common connection,, a switch controlling the ignition and means for radio shielding the apparatus on the generator side of said filter, said switch being between the spark plugs and the filter.

' 11. In an ignition system for an internal com- MELVILLE F. PETERS. R. HARRY STONE. 

